An integrated circuit contains various semiconductor devices and a plurality of conducting metal paths that provide electrical power to the semiconductor devices and allow these semiconductor devices to share and exchange information. Within the integrated circuit, metal layers are stacked on top of one another using intermetal or interlayer dielectric layers that insulate the metal layers from each other.
Normally, each metal layer must form an electrical contact to at least one additional metal layer. Such electrical contact is achieved by etching a hole (i.e., a via) in the interlayer dielectric that separates the metal layers, and filling the resulting via with a metal to create an interconnect. Metal layers typically occupy etched pathways in the interlayer dielectric. A “via” normally refers to any feature such as a hole, line or other similar feature formed within a dielectric layer that provides an electrical connection through the dielectric layer to a conductive layer underlying the dielectric layer. Similarly, metal layers connecting two or more vias are normally referred to as trenches.
The introduction of copper (Cu) metal into multilayer metallization schemes for manufacturing integrated circuits reduces the wiring resistance, and low permittivity or low dielectric constant (low-k) materials may be used as interlayer dielectrics (ILDs) to reduce the parasitic capacitance. Cu is known to easily diffuse into common integrated circuit materials such as silicon and dielectric materials, wherein Cu is a mid-bandgap impurity. Therefore, a diffusion barrier layer is formed onto dielectric materials and other materials in the integrated circuits to surround the Cu and prevent diffusion of the Cu into the integrated circuit materials. Fluorocarbon (CF) films comprising or consisting of fluorine and carbon are promising materials for use as low-k ILDs and other applications. However, a problem that is commonly encountered when attempting to integrate fluorocarbon films into semiconductor devices is weak adhesion between the fluorocarbon film and other material films in the devices which can result in blistering and/or peeling of the other material films from the fluorocarbon film.